| Research Abstract |
Using about 3,000 barley cultivars collected from different regions of the world, genetic variation at 7 isozyme loci was examined. A large variation was observed at each of 3 loci for esterase (Est-1, Est-2 and Est-4), since 4, 5 and 4 alleles were detected at those loci, respectively. Alleles at the esterase loci were distributed in the world with some regularity, and a large genetic diversity has been preserved in S.W. Asia where cultivated barley had been originated. At the other loci, namely, Aat-3 (aspartate aminotransferase), Aco-1 (aconitate hydratase), Pgd-1 and Pgd-2 (phospogluconate dehydrogenase), however, only 2 alleles were found, respectively, and mutant alleles at those loci were distributed in limited area; Nepal and India at Aat-3, Italy at Aco-1, and Nepal and Pakistan at Pdg-1. The mutant allele at Pgd-2 locus was frequently observed in Turkey and Europe, and it was also detected in northern parts of East Asis, especially of Japan, with some frequency. Such a geographical regularity of allelic distribution is thought to be resulted from the dispersal of cultivated barley.
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